Hello Marek,
Thank for your patch. Pm_runtime_put_sync is also done into function ltdc_crtc_mode_fixup.
To avoid several call of Pm_runtime_put_sync, it could be better to check pm_runtime activity:
+ int ret;
DRM_DEBUG_DRIVER("\n");
+ if (!pm_runtime_active(ddev->dev)) {
+ ret = pm_runtime_get_sync(ddev->dev);
+ if (ret) {
+ DRM_ERROR("Failed to enable crtc, cannot get sync\n");
+ return;
+ }
+ }
+
Best regards
Yannick Fertré
-----Original Message-----
From: Marek Vasut <marex@xxxxxxx>
Sent: samedi 29 février 2020 23:17
To: dri-devel@xxxxxxxxxxxxxxxxxxxxx
Cc: Marek Vasut <marex@xxxxxxx>; Yannick FERTRE <yannick.fertre@xxxxxx>; Philippe CORNU <philippe.cornu@xxxxxx>; Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxx>; Vincent ABRIOU <vincent.abriou@xxxxxx>; Maxime Coquelin <mcoquelin.stm32@xxxxxxxxx>; Alexandre TORGUE <alexandre.torgue@xxxxxx>; linux-stm32@xxxxxxxxxxxxxxxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Subject: [PATCH] drm/stm: repair runtime power management
Add missing pm_runtime_get_sync() into ltdc_crtc_atomic_enable() to match pm_runtime_put_sync() in ltdc_crtc_atomic_disable(), otherwise the LTDC might suspend via runtime PM, disable clock, and then fail to resume later on.
The test which triggers it is roughly -- run qt5 application which uses eglfs platform and etnaviv, stop the application, sleep for 15 minutes, run the application again. This leads to a timeout waiting for vsync, because the LTDC has suspended, but did not resume.
Fixes: 35ab6cfbf211 ("drm/stm: support runtime power management")
Signed-off-by: Marek Vasut <marex@xxxxxxx>
Cc: Yannick Fertré <yannick.fertre@xxxxxx>
Cc: Philippe Cornu <philippe.cornu@xxxxxx>
Cc: Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxx>
Cc: Vincent Abriou <vincent.abriou@xxxxxx>
Cc: Maxime Coquelin <mcoquelin.stm32@xxxxxxxxx>
Cc: Alexandre Torgue <alexandre.torgue@xxxxxx>
To: dri-devel@xxxxxxxxxxxxxxxxxxxxx
Cc: linux-stm32@xxxxxxxxxxxxxxxxxxxxxxxxxxxx
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
---
------------[ cut here ]------------
WARNING: CPU: 0 PID: 297 at drivers/gpu/drm/drm_atomic_helper.c:1494 drm_atomic_helper_wait_for_vblanks+0x1dc/0x200
[CRTC:35:crtc-0] vblank wait timed out
Modules linked in:
CPU: 0 PID: 297 Comm: QSGRenderThread Not tainted 5.6.0-rc3-next-20200228-00010-g318bf0fc08ef #2 Hardware name: STM32 (Device Tree Support) [<c010f18c>] (unwind_backtrace) from [<c010afb8>] (show_stack+0x10/0x14) [<c010afb8>] (show_stack) from [<c07b1d3c>] (dump_stack+0xb4/0xd0) [<c07b1d3c>] (dump_stack) from [<c011d8b8>] (__warn+0xd4/0xf0) [<c011d8b8>] (__warn) from [<c011dc4c>] (warn_slowpath_fmt+0x78/0xa8) [<c011dc4c>] (warn_slowpath_fmt) from [<c04a266c>] (drm_atomic_helper_wait_for_vblanks+0x1dc/0x200)
[<c04a266c>] (drm_atomic_helper_wait_for_vblanks) from [<c04a510c>] (drm_atomic_helper_commit_tail+0
x50/0x60)
[<c04a510c>] (drm_atomic_helper_commit_tail) from [<c04a52a8>] (commit_tail+0x12c/0x13c) [<c04a52a8>] (commit_tail) from [<c04a53b4>] (drm_atomic_helper_commit+0xf4/0x100)
[<c04a53b4>] (drm_atomic_helper_commit) from [<c04a2d38>] (drm_atomic_helper_set_config+0x58/0x6c)
[<c04a2d38>] (drm_atomic_helper_set_config) from [<c04b1994>] (drm_mode_setcrtc+0x450/0x550) [<c04b1994>] (drm_mode_setcrtc) from [<c04ad570>] (drm_ioctl_kernel+0x90/0xe8) [<c04ad570>] (drm_ioctl_kernel) from [<c04ad8ac>] (drm_ioctl+0x2e4/0x32c) [<c04ad8ac>] (drm_ioctl) from [<c0246784>] (vfs_ioctl+0x20/0x38) [<c0246784>] (vfs_ioctl) from [<c02470f0>] (ksys_ioctl+0xbc/0x7b0) [<c02470f0>] (ksys_ioctl) from [<c0101000>] (ret_fast_syscall+0x0/0x54) Exception stack(0xee8f3fa8 to 0xee8f3ff0)
3fa0: 00000005 adcbeb18 00000005 c06864a2 adcbeb18 00000001
3fc0: 00000005 adcbeb18 c06864a2 00000036 00000029 00000023 00000023 00000007
3fe0: b113b098 adcbeafc b1125413 b6155cf8 ---[ end trace 2ad5ba954ceb767a ]---
---
drivers/gpu/drm/stm/ltdc.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c index 99bf93e8b36f..301de0498078 100644
--- a/drivers/gpu/drm/stm/ltdc.c
+++ b/drivers/gpu/drm/stm/ltdc.c
@@ -425,9 +425,12 @@ static void ltdc_crtc_atomic_enable(struct drm_crtc *crtc,
struct drm_crtc_state *old_state) {
struct ltdc_device *ldev = crtc_to_ltdc(crtc);
+ struct drm_device *ddev = crtc->dev;
DRM_DEBUG_DRIVER("\n");
+ pm_runtime_get_sync(ddev->dev);
+
/* Sets the background color value */
reg_write(ldev->regs, LTDC_BCCR, BCCR_BCBLACK);
--
2.25.0
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